Using complex networks to analyze the Brazilian Chamber of deputies

• Ano de defesa: 2020
• Autor(a) principal: Brito, Ana Caroline Medeiros
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Brazilian political parties; Ciência política; Complex networks; Partidos políticos brasileiros; Political science; Redes complexas; Redes complexas sociais; Social complex networks
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/55/55134/tde-29102020-120145/

Complex networks are widely used to model individuals and their social interactions. In this research project, we use this representation to explore the voting data of Brazilian legislators of the Chamber of Deputies (from 1991 to 2019). When generating co-voting networks consisting of deputies as nodes connected by their similarity in their voting propositions behaviors, we aim to characterize political entities behavior: political parties cohesion, coalitions and their dynamics of emergence and dissolution. To this end, we defined a framework consisting of procedures in order to generate co-voting networks by year and, alternatively, by overlapping windows of three months; removal of less meaningful edges; communities identification; and the definition of isolation and fragmentation measures for groups characterization. The yearly networks analysis allows an overview of the Brazilian political scenario. For example, the most recent networks seem less cohesive than those in the early years, indicating that the deputies are overall in less agreement. The identified communities tend to represent the coalitions established among political parties. Furthermore, the effective number of communities reveals that there are few groups in comparison to the wide number of political parties in the Brazilian system. The characterization of these groups by using topological measures, revealed some interesting phenomenons, such as coalitions changes correlated with terms changes. The detailed analysis of the months before, during, and after the Rousseffs impeachment revealed that she did not have support of the Chamber of Deputies months before she left office.